Exemplary embodiments of the invention relate to a method for removing paint from a surface, and more particularly, to a method and assembly for locally removing paint using hazardous air pollutant (HAP) free chemicals.
Typically, the fuselage of an aircraft includes a metal substrate finished with one or more layers of paint or another coating, to protect the aircraft from environmental damage. The one or more layers may be removed from a designated portion of the metal substrate during manufacture or maintenance of the aircraft, such as for nondestructive inspection of a local area, electrical ground polishing for example, or alternatively during maintenance of the aircraft, such as to repair a damaged area for example.
Coatings of paint, primer, or the like are commonly removed by treating a desired portion of the aircraft with a stripping chemical mixture that includes a strong solvent having volatile chlorinated hydrocarbons, such as methylene chloride for example. When applied, the strong solvent causes the paint to swell and loosen and destroys the hydrogen bonds formed at the interface between the layer of paint and the metal substrate allowing the paint layer to dissociate from the underneath layer and to be scraped or peeled away from the adjacent surface. The most recent environmental, health, and safety regulations prohibit the use of methylene chloride based paint strippers and make the implementation of products free of Hazardous Air Pollutants (HAPs) a viable solution. These products often require repeated application of the stripping chemical mixture and/or application of heat to achieve the desirable stripping effectiveness.
Traditional removal of paint from large objects, such as an airplane, poses inherent dangers not only to the workers involved, but also to the surrounding environment. The chemicals used to remove paint are highly toxic, aggressive, and deleterious. As a result, safety regulations require workers to wear personal protective equipment and work in well-ventilated areas. In addition, during application, the liquid paint remover may run or drip down the aircraft and onto the un-designated area, which may cause damage to the surface of the area, and pose an environmental risk to the surrounding land and ground water as a result of runoff and drainage. The liquid paint remover may also run into faying surfaces, causing long term damage. Significant manufacturing time is added in the masking, preparation, and clean-up of the paint stripping process to minimize potential damage and environmental risk.